The present invention relates to a configuration and a related method wherein data are provided for characterizing various units on a bus system.
Such configurations and methods are required, for example but not exclusively, for the Universal Serial Bus (USB). The USB is a bus system designed in particular for use in computers. It is mainly used there for communication between the computer and peripherals connected to it, such as the mouse, the printer, and the like.
The units (end points) which are connected to the USB each have a data set which characterizes the respective unit and which contains various items of information about the respective unit itself (its address, its nature, etc) and about the communication with other units. The data set which characterizes the respective units is used in order to confirm whether the relevant unit is being addressed by a received data request, and in what way, if necessary, it should react to the data request.
Experience has shown that, particularly if the relevant unit is intended to be usable or operable in a flexible manner, the provision of the data which characterize a unit is associated with relatively high complexity.
It is accordingly an object of the invention to provide a configuration and method for providing data characterizing various units at a bus system, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which reduces to a minimum the complexity for providing the data which characterize a unit.
With the foregoing and other objects in view there is provided, in accordance with the invention, a configuration and a method for providing data characterizing various units on a bus system, comprising:
a plurality of memory elements having a variable content and receiving and storing some data characterizing a unit on a bus system; and hardware-defined connections determining a remainder of the data characterizing the unit on the bus system.
In other words, some of the data which characterize a unit are stored in memory elements having a variable content, and the rest of the data which characterize the unit are defined by hardware.
If a hardware definition is provided for those data items which are not allowed to be changed for the unit characterized by them or where such changes make no sense, and storage in memory elements having a variable content is provided for those data items which it may be necessary to change or may be worth changing, then the relevant unit can be used and operated flexibly and at the same timexe2x80x94in particular owing to the fact that the number of memory elements can be kept lowxe2x80x94can be physically small and can be operated with low power consumption and reliably (without being susceptible to defects).
In consequence, the complexity for providing the data which characterize a unit (an end point) on a bus system can be reduced to a minimum.
In accordance with an added feature of the invention, the data stored in the memory elements are generated in the unit characterized by the data, or supplied from an external memory.
In accordance with an additional feature of the invention, some of the data characterizing the unit are selectively formed by variable data or by data with a permanently set value.
In accordance with another feature of the invention, multiplexers are connected upstream or downstream to selected ones of the memory elements for selectively passing through the variable data or the data with the permanently set value.
In accordance with a further feature of the invention, the hardware-defined data received by the configuration are variable data.
In accordance with again an added feature of the invention, the data stored in the memory elements are coded data which, before being output, are converted into the data that characterize the respective unit.
In accordance with again a further feature of the invention, the hardware data and/or data set to permanent values are selected such that an absence of the unit characterized by the data is signaled by the data to the receiver thereof.
In accordance with a concomitant feature of the invention, the unit characterized by the data is an end point of a Universal Serial Bus System.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an configuration and method for providing data for characterization of various units on a bus system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.